A Turkish prosecutor is considering whether to prosecute the Turkish publisher of Richard Dawkins' bestselling atheist polemic, The God Delusion, on the grounds that it incites religious hatred.

The publisher, Erol Karaaslan, said today that he expected to be questioned on Thursday by an Istanbul prosecutor as part of an official investigation, and faces prosecution both as its publisher and translator. The book has sold some 6,000 copies in Turkey since it was published by his Kuzey publishing house in June. The inquiry apparently began after one reader complained that passages in the book were an assault on "sacred values".

The investigation comes in the wake of controversy over the issue of freedom of speech in Turkey after Orhan Pamuk's prosecution in 2005. The Nobel prize-winner was tried under Article 301 of the Turkish criminal code for "insulting Turkishness" following comments he made to a Swiss magazine to the effect that a million Armenians had died in Turkey during the first world war - "and nobody but me dares to talk about it". The charges were eventually dropped. The author Elif Shafak, too, was last year acquitted of similar charges brought over remarks made by a character in her latest novel, The Bastard of Istanbul.

Karaaslan could be required to stand trial if the prosecutor concludes that Dawkins' book incites religious hatred and insults religious values, and would face up to one year in prison if found guilty, according to the Turkish daily newspaper Milliyet.

The European Union, which Turkey hopes to join, is pressing Ankara to change laws that curb free expression and do not conform to the Union's standards of free speech.